Article of footwear

ABSTRACT

An article of footwear includes an upper formed of a base layer, a reinforcement layer, and an auxetic structure coupled to the reinforcement layer. The base layer includes an elastic material and is elastically deformable between a resting configuration and a stretched configuration. The base layer is configured to be stretched to a predetermined amount. The inelastic reinforcement layer is coupled to the base layer. The reinforcement layer is configured to delimit the stretch amount of the base layer when the base layer is in the stretched configuration.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a nonprovisional of provisional application62/782,423, filed 20 Dec. 2018 and entitled “Stretch Material withLockout Feature,” the disclosure of which is incorporated herein byreference in its entirety.

FIELD

This document relates to an article of footwear, and particularly tofootwear including an upper with predetermined stretch properties.

BACKGROUND

Many articles of apparel are designed to fit closely to the human body.When designing an article of apparel for a close fit to the human body,different body shapes and sizes must be considered. Differentindividuals within a particular size will have different body shapes andsizes. For example, two individuals wearing the same shoe size may havevery differently shaped feet. As another example, two individualswearing the same shirt size may have very different chest to abdomendimensions. In addition to accounting for different body measurementsfor different individuals within a size, articles of apparel designed tofit close to the human body may also need to provide sufficient strengthand support for the user. For example, when fabric is used on a shoe,the fabric must be capable of supporting the foot of the wearer andlimiting movement of the foot within the shoe. The need for propersupport in combination with variable measurements between similarlysized individuals makes proper design of closely fitting articles ofapparel difficult.

In view of the foregoing, it would be desirable to provide a garment orother article of apparel comprised of a fabric that is capable ofconforming to various body shapes within a given size range. It wouldalso be desirable to provide a fabric that is strong and capable ofproviding proper support to various areas on the human body.Furthermore, it would be advantageous for such fabric to be comfortableagainst human skin while also managing perspiration and moisture for thewearer. In addition, it would be desirable for such a garment or articleof apparel to be attractive, relatively inexpensive and easy tomanufacture.

SUMMARY

In accordance with one exemplary embodiment of the disclosure, there isprovided an article of apparel that comprises a base layer, areinforcement layer, and an auxetic structure. The base layer comprisesan elastic material, and the base layer is elastically deformablebetween a resting configuration and a stretched configuration. The baselayer is stretched a stretch amount when in the stretched configuration.The reinforcement layer is coupled to the base layer. The reinforcementlayer is configured to delimit the stretch amount of the base layer whenthe base layer is in the stretched configuration. The auxetic structureis coupled to the reinforcement layer.

Pursuant to another exemplary embodiment of the disclosure, there isprovided an upper for an article of footwear that comprises a baselayer, a reinforcement layer, and a material. The base layer comprisesan elastic material, and the base layer is elastically deformablebetween a resting configuration and a stretched configuration. The baselayer is stretched a stretch amount when in the stretched configuration.The reinforcement layer is coupled to the base layer. The reinforcementlayer is configured to delimit the amount of stretch of the base layerwhen the base layer is in the stretched configuration. The material isapplied to the reinforcement layer. The material forms a structuredefining a repeating pattern of perimeter walls and interior recesses.

In accordance with yet another exemplary embodiment of the disclosure,there is provided a method of manufacturing a panel for an article ofapparel. The method includes stretching a base layer from a restingconfiguration to a stretched configuration. The method further includescoupling a reinforcement layer to the base layer when the base layer isin the stretched configuration. The method also includes applying anauxetic structure to the reinforcement layer when the base layer is inthe stretched configuration. The auxetic structure includes a pluralityof interconnected members defining a repeating pattern of voids, andeach void has a reentrant shape. The method further includes releasingthe base layer to allow the base layer to return to the restingconfiguration.

The above described features and advantages, as well as others, willbecome more readily apparent to those of ordinary skill in the art byreference to the following detailed description and accompanyingdrawings. While it would be desirable to provide an article of appareland a method that provides one or more of these or other advantageousfeatures, the teachings disclosed herein extend to those embodimentswhich fall within the scope of the appended claims, regardless ofwhether they accomplish one or more of the above-mentioned advantages.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exploded perspective view of a panel of an article ofapparel including a base layer, a reinforcement layer, an auxetic layer,and a lining layer.

FIG. 2 is an exploded plan view of the base layer, the reinforcementlayer, the auxetic layer, and the lining layer of FIG. 1.

FIG. 3A is a plan view of one embodiment of an auxetic structure of theauxetic layer of FIG. 1 including segments and voids forming a pluralityof reentrant shapes.

FIG. 3B is a plan view of the auxetic structure of FIG. 3A in anexpanded position.

FIG. 4A is a panel of the auxetic layer including the auxetic structureof FIG. 3A applied to a substrate material.

FIG. 4B is an enlarged, schematic view of the auxetic layer of FIG. 4A,showing dimensions of the auxetic layer.

FIG. 4C is a cross-sectional view of an exemplary embodiment of theauxetic layer of FIG. 4A.

FIG. 5A is a plan view of an alternative embodiment of the auxeticstructure of the auxetic layer of FIG. 1.

FIG. 5B is a plan view of another alternative embodiment of the auxeticstructure of the auxetic layer of FIG. 1.

FIG. 6 is a flowchart illustrating a method of making the panel of thearticle of apparel of FIG. 1.

FIG. 7A is a diagram illustrating the base layer of the panel of FIG. 1in a resting configuration in an embodiment of the panel formed byadhesion.

FIG. 7B is a diagram illustrating the base layer of FIG. 7A in astretched configuration.

FIG. 7C is a diagram illustrating the base layer of FIG. 7A in thestretched configuration and the reinforcement layer of the panel of FIG.1 in an embodiment of the panel formed by adhesion.

FIG. 7D is a diagram illustrating the base layer of FIG. 7A in thestretched configuration, and the reinforcement layer and the auxeticlayer of the panel of FIG. 1 in an embodiment of the panel formed byadhesion.

FIG. 7E is a diagram illustrating the panel of FIG. 1 in an embodimentof the panel formed by adhesion including the base layer of FIG. 7A inthe stretched configuration.

FIG. 7F is a diagram illustrating the panel of FIG. 1 in an embodimentof the panel formed by adhesion including the base layer of FIG. 7A in aresting configuration.

FIG. 7G is a diagram illustrating the panel of FIG. 1 in a stretchedconfiguration.

FIG. 8A is a diagram illustrating the base layer of the panel of FIG. 1in a resting configuration in an embodiment of the panel formed bystitching.

FIG. 8B is a diagram illustrating the base layer of FIG. 8A in astretched configuration.

FIG. 8C is a diagram illustrating the base layer of FIG. 8A in thestretched configuration and the reinforcement layer of the panel of FIG.1 in an embodiment of the panel formed by stitching.

FIG. 8D is a diagram illustrating the base layer of FIG. 8A in thestretched configuration, and the reinforcement layer and the auxeticlayer of the panel of FIG. 1 in an embodiment of the panel formed bystitching.

FIG. 8E is a diagram illustrating the panel of FIG. 1 in an embodimentof the panel formed by stitching including the base layer of FIG. 8A inthe stretched configuration.

FIG. 8F is a diagram illustrating the panel of FIG. 1 in an embodimentof the panel formed by stitching including the base layer of FIG. 8A ina resting configuration.

FIG. 8G is a diagram illustrating the panel of FIG. 1 in a stretchedconfiguration.

FIG. 9A is a perspective view of an exemplary embodiment of the panel ofFIG. 1 applied to an article of footwear.

FIG. 9B is a rear view of the article of footwear shown in FIG. 9A.

FIG. 10 is a perspective view of another exemplary embodiment of thepanel of FIG. 1 applied to an article of footwear.

FIG. 11A is a lateral side view of an article of footwear in accordancewith the invention.

FIG. 11B is a perspective view of the article of footwear shown in FIG.11A.

FIG. 11C is a top view of the article of footwear shown in FIG. 11A.

Like numerals have been utilized to identify like components throughoutthe figures.

DETAILED DESCRIPTION

As for the purpose of promoting an understanding of the principles ofthe disclosure, reference will now be made to the embodimentsillustrated in the drawings and described in the following writtenspecification. It is understood that no limitation to the scope of thedisclosure is thereby intended. It is further understood that thisdisclosure includes any alterations and modifications to the illustratedembodiments and includes further applications of the principles of thedisclosure as would normally occur to one skilled in the art to whichthis disclosure pertains.

In the following detailed description, reference is made to theaccompanying drawings which form a part hereof wherein like numeralsdesignate like parts throughout, and in which is shown, by way ofillustration, embodiments that may be practiced. It is to be understoodthat other embodiments may be utilized, and structural or logicalchanges may be made without departing from the scope of the presentdisclosure. Therefore, the following detailed description is not to betaken in a limiting sense, and the scope of embodiments is defined bythe appended claims and their equivalents.

Aspects of the disclosure are disclosed in the accompanying description.Alternate embodiments of the present disclosure and their equivalentsmay be devised without parting from the spirit or scope of the presentdisclosure. It should be noted that any discussion herein regarding “oneembodiment,” “an embodiment,” “an exemplary embodiment,” and the likeindicate that the embodiment described may include a particular feature,structure, or characteristic, and that such particular feature,structure, or characteristic may not necessarily be included in everyembodiment. In addition, references to the foregoing do not necessarilycomprise a reference to the same embodiment. Finally, irrespective ofwhether it is explicitly described, one of ordinary skill in the artwould readily appreciate that each of the particular features,structures, or characteristics of the given embodiments may be utilizedin connection or combination with those of any other embodimentdiscussed herein.

Various operations may be described as multiple discrete actions oroperations in turn, in a manner that is most helpful in understandingthe claimed subject matter. However, the order of description should notbe construed as to imply that these operations are necessarily orderdependent. In particular, operations described may be performed in adifferent order than the described embodiments. Various additionaloperations may be performed and/or described operations may be omittedin additional embodiments.

For the purposes of the present disclosure, the phrase “A and/or B”means (A), (B), or (A and B). For the purposes of the presentdisclosure, the phrase “A, B, and/or C” means (A), (B), (C), (A and B),(A and C), (B and C), or (A, B and C).

The terms “comprising,” “including,” “having,” and the like, as usedwith respect to embodiments of the present disclosure, are synonymous.

With reference now to FIG. 1, an article of apparel includes at leastone panel 100 comprising an elastic base layer 104, a reinforcementlayer 108, an auxetic layer 110 including an auxetic structure 112applied to a substrate material 140, and a lining 116 (also referred toherein as a “lining layer”). The reinforcement layer 108 is coupled tothe base layer 104, the auxetic structure 112 is coupled to thereinforcement layer 108, and the lining 116 is coupled to the base layer104 opposite the reinforcement layer 108. As described in more detailbelow, the panel 100 is assembled with the elastic base layer 104 in astretched state. When the base layer 104 is released after assembly, thebase layer 104 returns to a relaxed state, but the other layers 108, 112and 116 are pulled inwardly along with the base layer 104 and experiencea significant amount of buckling and folding. When the panel 100 issubsequently stretched during use, the reinforcement layer 108 limitsthe amount of stretch of the panel 100.

The term “article of apparel” as used herein refers to any garment,footwear or accessory configured to be worn on or carried by a human.Examples of articles of apparel include helmets, hats, caps, shirts,pants, shorts, sleeves, knee pads, elbow pads, shoes, boots, backpacks,duffel bags, cinch sacks, and straps, as well as numerous other productsconfigured to be worn on or carried by a person.

The base layer 104 is made of an elastic material that is elasticallydeformable between a resting configuration and a stretchedconfiguration. More specifically, the elastic material of the base layer104 is deformed by stretching from a resting configuration to astretched configuration under applied tension, also referred to astensile stress, and returns to its original shape in the restingconfiguration when the applied tension is released. The elastic materialof the base layer 104 has an elastic limit, beyond which the applicationof additional tension deforms the elastic material irreversibly. Theelastic material of the base layer 104 also has an elastic modulus,which determines how much tension must be applied for the elasticmaterial to stretch. Accordingly, the elastic modulus of the elasticmaterial also determines how strongly the material will retract toreturn to its resting configuration when released from the appliedtension.

In the stretched configuration, the elastic material of the base layer104 is stretched a stretch amount, which is less than the elastic limitof the elastic material. Accordingly, when the applied tension isreleased from the elastic material, the base layer 104 returns to theresting configuration. Each of the elastic limit and the elastic modulusof the elastic material of the base layer 104 is high enough to enablethe base layer 104 to return to the resting configuration after beingstretched the stretch amount by donning, wearing, and/or using thearticle of apparel. Additionally, the elastic modulus of the elasticmaterial of the base layer 104 is low enough to enable the base layer104 to be stretched from the resting configuration during normaldonning, wearing, and/or using the article of apparel.

The elastic material of the base layer 104 may be formed from any ofvarious materials provided in any of various configurations, such asknit or woven fabrics. In the embodiment of FIG. 2, the elastic materialof the base layer 104 is a fine, flexible mesh or woven fabric having aplurality of base layer openings 120 formed between a plurality of baselayer threads 124. The base layer threads 124 are formed from a polymer.In at least one exemplary embodiment, the base layer threads 124comprise polyester and elastane.

In at least one embodiment, the base layer 104 comprises a resilientmaterial having selected stretch capabilities, e.g., four-way or two-waystretch capabilities. A material with “four-way” stretch capabilitiesstretches in a first direction and a second, directly-opposingdirection, as well as in a third direction that is perpendicular to thefirst direction and a fourth direction that is directly opposite thethird direction. In other words, a sheet of four-way stretch materialstretches in both crosswise and lengthwise. A material with “two-way”stretch capabilities, in contrast, stretches to a substantial degree inthe first direction and the second, directly opposing direction, butwill not stretch in the third and fourth directions, or will onlystretch to a limited degree in the third and fourth directions relativeto the first and second directions (i.e., the fabric will stretchsubstantially less in the third and fourth directions than in the firstdirection and second directions). In other words, a sheet of two-waystretch material stretches either crosswise or lengthwise.

In the embodiments disclosed herein, the base layer 104 is formed of amicrofiber four-way stretch fabric such as elastane fabric or othercompression material including elastomeric fibers (e.g., a knittedfabric comprising greater than 50% elastane (e.g., 65% or more)). Inother embodiments, the base layer 104 is comprised of an elastic fabrichaving limited stretch properties, such as a two-way stretch fabric.

In contrast to the elastic material of the base layer 104, thereinforcement layer 108 is made of a material that is relativelyinelastic. More specifically, while the material of the reinforcementlayer 108 is somewhat elastically deformable (having an elastic limitand an elastic modulus) it is inelastic in comparison to the elasticmaterial of the base layer 104. Therefore, the material of thereinforcement layer 108 has a higher elastic modulus than the elasticmaterial of the base layer 104, and the material of the reinforcementlayer 108 does not stretch as easily as the elastic material of the baselayer 104 under the same applied tension. The material of thereinforcement layer 108 also has a high elastic limit relative to theamount of stress that will be applied to the reinforcement layer 108during normal donning, wearing, and/or using of the article of apparel.Accordingly, the material of the reinforcement layer 108 stretches verylittle or not at all and is unlikely to be permanently deformed ordamaged under the application of normal human forces during donning,wearing and/or using the article of apparel.

As shown in FIG. 2, the material of the reinforcement layer 108 is amatrix mesh having a plurality of reinforcement layer openings 128, alsoreferred to as apertures, formed between a plurality of reinforcementlayer strands 132. The reinforcement layer strands 132 are formed from apolymer and are woven or otherwise attached together to form a square ormatrix mesh, resembling a grid. It should be understood that while thereinforcement layer strands 132 have been described as being a square ormatrix mesh that resembles a grid, in alternative embodiments, thereinforcement layer strands 132 can form a mesh having a different shapeor arrangement. One advantage of the square mesh is that the grid shapewith square openings is readily formed and retained by melting thepolymer reinforcement layer strands 132 together in the desiredconfiguration. In at least one exemplary embodiment, the reinforcementlayer strands 132 comprise nylon.

As shown in FIG. 2, the reinforcement layer openings 128 are larger thanthe base layer openings 120 and are large enough to enable the materialof the auxetic structure 112 to pass through and/or infiltrate thereinforcement layer 108 to couple the reinforcement layer 108 to thebase layer 104 as described in further detail below.

In a further embodiment, the reinforcement layer is a warp knittedfabric (e.g., tricot) formed of nylon.

When the reinforcement layer 108 is coupled to the base layer 104 bystitching, by adhesion, or by another known means which retains themajority of the surface area of the reinforcement layer 108 in contactwith the majority of the surface area of the base layer 104. Because thematerial of the reinforcement layer 108 has a higher elastic modulusthan the elastic material of the base layer 104, when the reinforcementlayer 108 is coupled to the base layer 104, the reinforcement layer 108limits the stretch of the base layer 104.

The auxetic layer 110 includes the auxetic structure 112 coupled to thesubstrate material 140. As described in further detail below, theauxetic structure 112 is coupled or otherwise applied to the substratematerial 140 in any one of a number of different manners, including, forexample, printing onto the substrate material 140, adhesion to thesubstrate material 140, or stitching or embroidering into the substratematerial 140. In any case, as described in more detail below, in thepanel 100, the substrate material 140 is coupled to the reinforcementlayer 108, opposite the base layer 104, by the auxetic structure 112,and the auxetic structure 112 is also coupled to the reinforcement layer108.

The substrate material 140 is a flexible and/or resilient layer operableto permit the expansion of the auxetic structure 112 when tensile stressis applied to the panel 100. In an embodiment, the substrate material140 comprises a resilient material having selected stretch capabilities,e.g., two-way stretch capabilities. By way of example, the substratematerial 140 is formed of a nonwoven fabric. In further embodiments, thesubstrate is a non-stretch or low-stretch material such as a syntheticleather (e.g., 0.8 mm CLARINO™ leather available from Kururay America).

The term “auxetic” as used herein generally refers to a material orstructure possessing a negative Poisson's ratio. In other words, whenstretched, auxetic materials or structures expand, becoming thicker (asopposed to thinner), in a direction perpendicular to the applied force.In at least one embodiment, this expansion occurs due to inherenthinge-like configurations within the materials or structures which flexwhen stretched. In contrast, materials or structures with a positivePoisson's ratio contract in a direction perpendicular to the appliedforce. In other embodiments, the structure applied to the substratematerial (stitching or adhesive as described below), while not achievinga negative Poisson's ratio, lowers the Poisson's ratio of the material(compared to a material lacking the structure).

One exemplary auxetic structure 112 is shown in FIGS. 3A and 3B. Theauxetic structure 112 is provided by a plurality ofgenerally-polygon-shaped cells (e.g., hourglass or bow-tie shaped cells,which may also be referred to as “auxetic hexagons”). The cells areoriented in an array, being positioned in horizontal rows and verticalcolumns. FIG. 3A shows the auxetic structure 112 in its normal,unstretched state. The thickness (or width) of the auxetic structure inthe unstretched state is indicated as d1. FIG. 3B shows the auxeticstructure 112 stretched in the direction of arrows 12. The thickness ofthe auxetic structure in the stretched state is indicated by d2. As canbe seen in FIG. 3B, when tension is applied along a first direction(indicated by arrows 12), the auxetic structure is stretched, expanding(becoming thicker) in a second direction perpendicular to the firstdirection 12 (indicated by arrows 13) such that, in the stretched stated2>d1. In the embodiment of FIGS. 3A and 3B, this phenomenon is theresult of the pivoting/rotation that occurs along the vertices of theshape, i.e., where the corners of the polygons intersect.

It will be recognized that whether a structure has a negative Poisson'sratio may depend upon the degree to which the structure is stretched.Structures may have a negative Poisson's ratio up to a certain stretchthreshold, but when stretched past the threshold may have a positivePoisson's ratio. For example, it is possible that when the auxeticstructure 112 in FIG. 3A is stretched in the direction of arrows 12 pasta threshold expansion position (e.g., past the state shown in FIG. 3B),the cells and segments of the auxetic structure 112 may be stretched toan extent that the auxetic structure 112 becomes slightly thinner (inthe direction perpendicular to arrows 12) before the structure is tornapart or otherwise damaged. Accordingly, the term “auxetic” as usedherein refers to structures or materials that possess or exhibit anegative (below zero) Poisson's ratio at some point during stretch.Preferably, the structure or material possesses a negative Poisson'sratio during the entirety of the stretch. The term “near auxetic,”moreover, is used herein to refer to a structure having a Poisson'sratio of approximately zero and, in particular, less than +0.15 (i.e.,from about 0 to +0.15).

Auxetic structures are formed from a plurality of interconnectedsegments forming an array of cells, and each cell having a reentrantshape. In the field of geometry, a reentrant shape may also be referredto as a “concave”, or “non-convex” polygon or shape, which is a shapehaving an interior angle with a measure that is greater than 180°. Theauxetic structure 112 in FIGS. 3A and 3B is an example of such astructure including a reentrant shape. As shown, interior angle αpossesses a measurement of greater than 180°.

Auxetic structures may be defined by two different elongationdirections, namely, a primary elongation direction and a secondaryelongation direction. The primary elongation direction is a firstdirection along which the cells of the auxetic structure are generallyarranged, and the secondary elongation direction is the directionperpendicular to the first direction, the cells of the auxetic structurealso being arranged along this second direction. For example, in FIGS.3A and 3B, the horizontal arrows 12 (from the viewpoint of FIG. 3Bdefine the primary elongation direction, while vertical arrows 13 (fromthe viewpoint of FIG. 3B) define the secondary elongation direction.When a tension force elongates the auxetic structure 112 in the primaryelongation direction, the auxetic structure is also elongated in thesecondary elongation direction. Similarly, applying tension to theauxetic structure 112 in the secondary elongation direction will resultin elongation in the primary elongation direction.

The total number of cells, the shape of each shell, and the overallarrangement of the cells within the structure generate the expansionpattern of the auxetic structure. That is, the arrangement and shape ofthe cells determine whether the auxetic structure 112 expands a greateramount in the primary elongation direction or the secondary elongationdirection.

It should be noted that the phrases “primary elongation direction” and“secondary elongation direction” as used herein do not necessarilyindicate that the auxetic structure 112 elongates further in onedirection or the other but is merely used to indicate two generaldirections of elongation for the auxetic structure as defined by thecells, with one direction being perpendicular to the other. Accordingly,the term “primary elongation direction” is used merely for convenienceto define one direction of stretch. However, once one direction ofstretch is defined as the “primary elongation direction”, the term“secondary elongation direction”, as used herein, refers to a directionthat is perpendicular to the primary elongation direction. For example,for auxetic structures having polygon shaped cells with two or moresubstantially parallel opposing edges, such as those shown in FIGS. 3Aand 3B (e.g., edges 11 a and 11 b in FIGS. 3A and 3B), the primaryelongation direction may be a line that extends perpendicularly throughthe substantially parallel opposing edges (e.g., edges 11 a and 11 b) ofthe cells. Thus, in the auxetic structure of FIGS. 3A and 3B, theprimary elongation direction may be defined by arrows 12. However, asnoted above the primary elongation direction may alternatively bedefined to be the perpendicular direction defined by arrows 13. Ineither case, the secondary elongation direction is the directionperpendicular to the primary elongation direction.

The auxetic structure 112 is an open framework capable of supporting thesubstrate material 140 and directing the expansion of the substratematerial 140 under applied tension. Accordingly, the auxetic structure112, though flexible, may be stiffer than the substrate material 140(i.e., the segments forming the auxetic structure 112 possess a higherelastic modulus than the substrate material 140). The auxetic structure112 and the substrate material 140, in combination, are also referred toherein as the auxetic layer 110.

FIGS. 4A-4C show one exemplary embodiment of the auxetic structure 112applied to the substrate material 140. As shown, the auxetic structure112 is a plurality of segments 24 arranged to provide a repeatingpattern or array of cells 26, each cell possessing a reentrant shape.Specifically, each cell 26 is defined by a set of interconnectedstructural members 24 a, 24 b, 24 c, 24 d, 24 e, 24 f, with an apertureor void 28 formed in the center of the cell 26. Such structural membersmay also be referred to as perimeter walls, and such voids may also bereferred to as interior recesses. The void 28 exposes the substratematerial 140 to which the auxetic structure 112 is coupled. Accordingly,the auxetic structure 112 is a mesh framework defined by segments 24 andvoids 28.

In at least one embodiment, the auxetic structure 112 is a unitarystructure, with each cell 26 sharing segments 24 with adjacent cells.The cells 26 form an array of reentrant shapes, including a plurality ofrows and columns of shapes defined by the voids 28. For example, in theembodiment of FIG. 4A, the reentrant shapes are bow-tie shapes (orauxetic hexagon shapes, similar to the shapes shown in FIGS. 3A and 3B).However, it will be recognized by those of ordinary skill in the artthat the cells 26 of the auxetic structure 112 may include differentlyshaped segments or other structural members and differently shapedvoids. FIGS. 5A and 5B show two exemplary alternative auxeticstructures. In FIG. 5A, the cells 26 of the auxetic structure 112 have atwisted triangular or triangular vortex shape, and the interconnectedstructural members are curved segments. In FIG. 5B, the cells 26 areoval shaped, and the interconnected structural members are rectangularor square structures.

In at least one embodiment, the segments 24 possess uniform dimensions.With reference again to the exemplary embodiment of FIGS. 4A and 4B, inan embodiment, the segments 24 forming the cells 26 (i.e., the cellstructural members 24 a-24 f) are not necessarily uniform in shape andthickness. In particular, as shown in FIG. 4B, segment 24 a is slightlybowed or convex along its length while segment 24 b is substantiallystraight along its length. Segment 24 a has a width, w, of between lmmand 5 mm, and particularly 3 mm. Segment 24 b has a width, x, between0.5 mm and 4 mm, and particularly 2 mm. While the segments 24 may varysomewhat in size and shape, the voids 28 are substantially uniform insize and shape. In the embodiment of FIG. 4B, the cell voids 28 have aheight, y, between 6 and 12 mm, and particularly about 9.3 mm. The cellvoids 28 have a width, z, between 6 and 12 mm, and particularly about8.8 mm. Although not illustrated in FIG. 4B, the cross-sectionalthickness of each segment 24 may be between 0.5 mm and 5 mm, and morespecifically in some embodiments, between 1 mm and 2 mm, andparticularly about 1.5 mm.

In order to design the auxetic layer 110 with desirable qualities, anumber of design considerations must be balanced. These designconsiderations include, for example, the proximity of negative space(i.e., the proximity of the voids 28 associated with each cell 26), thecell size, the stroke distance (i.e., the distance a cell expandsbetween a retracted position and a fully extended position), the mass,elasticity and strength of the material used for the cell walls. Thesedesign considerations must be carefully balanced to produce an auxeticlayer 110 with the desired qualities. For example, for a given material,the larger the voids in each cell, the more flexible the resultingauxetic layer 110. Conversely, for the same material, the smaller thevoids in each cell, the more rigid and resistant to expansion theresulting auxetic layer 110.

In at least one embodiment, it is desirable for the auxetic structure112 to be more dominant than the substrate material 140 such thatapplication of a tensile stress to the auxetic layer 110 will result inthe more submissive substrate material 140 conforming to any changes inthe more dominant auxetic structure 112. Accordingly, in suchembodiment, the cell walls must be designed such that the resultingauxetic structure 112 will be more dominant than the material of thesubstrate material 140. Selection of the substrate material 140 relativeto the auxetic structure 112 permits the control of the auxetic layerstretch pattern and/or the auxetic structure stretch pattern (discussedin greater detail below).

It should be understood that, while the substrate material 140 has beendescribed as being formed of a stretch fabric, in other embodiments, thesubstrate material 140 may be comprised of other resilient materials,including any of various elastomers such as thermoplastic polyurethane(TPU), nylon, or silicone (e.g., a plastic sheet formed of resilientplastic). Furthermore, when the substrate material 140 is comprised ofan elastomer, the substrate material 140 may be integrally formed withthe auxetic structure 112 to provide a continuous sheet of material thatis seamless and without constituent parts.

With various configurations of the auxetic structure 112 and thesubstrate material 140, then, it is possible to control the overallstretch/expansion pattern of the auxetic layer 110 by combining theindividual properties of the auxetic structure 112 and the substratematerial 140. By way of example, it is possible to provide a non-auxeticlayer with auxetic properties. In an embodiment, the substrate material140 is four-way stretch material that, by itself, is not auxetic (i.e.,it exhibits a positive Poisson's ratio under load). Accordingly, whenthe substrate material 140 is separate from the auxetic structure 112and tension is applied across the auxetic layer material, the auxeticlayer material contracts in the direction perpendicular to the appliedtension. Superimposing the auxetic structure 112 over the substratematerial 140, however, provides a framework sufficient to drive theexpansion pattern of the substrate material 140. As a result, thesubstrate material 140 in combination with the auxetic structure 112will follow the expansion pattern of the auxetic structure 112,expanding not only along the axis of the applied tensile strain, butalso along the axis perpendicular to the axis of the applied tensilestrain. The resiliency of the substrate material 140, moreover,optimizes the contouring ability of the auxetic layer 110 since ittightly conforms to the surface of the wearer. Furthermore, thesubstrate material 140, being resilient, limits the expansion of theauxetic layer 110 to that necessary to conform to the object. That is,the substrate material 140, while permitting expansion of the auxeticstructure 112, will draw the arrangement back towards its normal/staticposition. Accordingly, over expansion of the auxetic structure 112 isavoided.

Additionally, it is possible to limit the auxetic properties of theauxetic layer 110 by selecting an appropriate substrate material 140.When forming apparel (e.g., footwear), while expansion is desired, it isoften desirable to limit the degree of expansion along one or more axes.By selecting a substrate material 140 of two-way stretch material, it ispossible to limit the expansion along a selected axis. Specifically,mounting an auxetic structure 112 onto a substrate material 140 formedof two-way stretch material permits the expansion of the auxetic layer110 along an axis parallel to the two-way stretch direction of thesubstrate material 140, but limits expansion of the auxetic layer 110along an axis perpendicular to the two-way stretch direction of thesubstrate material 140. Accordingly, application of a tensile stressalong the two-way stretch direction of the substrate material 140results in significant expansion of the auxetic layer 110 along thetwo-way stretch direction, but only limited or no expansion of theauxetic layer 110 along the axis perpendicular to the two-way stretchdirection. Application of a tensile stress along the axis perpendicularto the two-way stretch direction results in limited or no expansion ofthe auxetic layer 110 in either direction. In this manner, an article ofapparel may possess a customized stretch direction, including aplurality of auxetic structures 112 and auxetic layers 140 selected andpositioned to provide optimum stretch properties to the apparel.

Thus, in embodiments where the substrate material 140 has two-way orfour-way stretch properties, the orientation of the substrate material140 relative to the auxetic structure 112 may influence the overallstretch properties of the auxetic layer 110. For example, consider apanel 100 with a substrate material 140 having two-way stretchproperties configured such that the two-way stretch direction of thesubstrate material 140 is aligned with a stretch direction of theauxetic structure 112 (e.g., the two-way stretch direction of thesubstrate material 140 is aligned with the arrows 12 shown on theauxetic structure 112 in the embodiment of FIG. 3B). The Poisson's ratioexhibited by this panel 100 may tend to be closer to zero, or “nearzero”, than would be exhibited by a panel 100 including a substratematerial 140 with four-way stretch properties. Because the substratematerial 140 limits stretch in the perpendicular direction (e.g., in thedirection of arrows 13 in FIG. 3B), the stretch of the panel 100 will belimited in this perpendicular direction, thus keeping the Poisson'sratio for the panel closer to zero.

Finally, the auxetic layer 110 forms a more supportive structure thaneither the auxetic structure 112 or the substrate material 140 alone.That is, the auxetic layer 110 described above provides an openframework that functions as a support structure for the article ofapparel. For example, when used to form an upper in an article offootwear, the auxetic layer 110 may be generally self-supporting.

As shown in FIG. 1, the lining layer 116 is coupled to the base layer104 opposite the reinforcement layer 108. Like the reinforcement layer108, the lining layer 116 is made of a material that is relativelyinelastic. More specifically, the material of the lining layer 116 isinelastic in comparison to the elastic material of the base layer 104.Therefore, the material of the lining layer 116 has a higher elasticmodulus than the elastic material of the base layer 104, and thematerial of the lining layer 116 does not stretch as easily as theelastic material of the base layer 104 under the same applied tension.The material of the lining layer 116 also has a high elastic limitrelative to the amount of stress that will be applied to thereinforcement layer 108 during normal donning, wearing, and/or using ofthe article of apparel. Accordingly, the material of the lining layer116 stretches very little to none and is unlikely to be permanentlydeformed or damaged under the application of normal human forces duringdonning, wearing and/or using the article of apparel.

In various embodiments, the lining layer 116 is a knit fabric of nylonor polyester yarns. In embodiments where the panel 100 is used in anupper of an article of footwear, the lining layer 116 is made of amaterial that has a high puncture resistance. For example, in suchembodiments, the lining layer 116 is puncture resistant under forcesabove 450 Newtons. Such puncture resistance is particularly advantageousin cleated sports, such as baseball, football, and soccer, to protectthe integrity of the article of footwear, as well as the user's foottherein, in the event of contact with the cleats of another article offootwear. In alternative embodiments, the lining layer 116 is punctureresistant under forces other than those above 450 Newtons.

The lining layer 116 is the innermost layer of the panel 100.Accordingly, when the panel 100 is integrated into an article ofapparel, the lining layer 116 faces inwardly toward itself and/or towardthe body of a wearer or user of the article of apparel. Thus, thematerial of the lining layer 116 is typically also a material that iscomfortable in contact with the skin of a wearer or user. In somealternative embodiments, the panel 100 does not require the lining layer116. In such embodiments, the base layer 104 is the innermost layer ofthe panel 100.

As shown in FIG. 6, the panel 100 is formed by combining the layersdescribed above. More specifically, FIG. 6 depicts a method 200 forforming the panel 100. First, the base layer is stretched from theresting configuration to the stretched configuration (block 204). Then,the reinforcement layer is applied to the base layer, while the baselayer is still in the stretched configuration (block 208). Next, theauxetic layer is applied to the reinforcement layer on the opposite sideof the reinforcement layer as the base layer (block 212). The base layeris still in the stretched configuration for the application of thereinforcement layer. The auxetic layer, the reinforcement layer, and thebase layer are all coupled together to form a unitary structure (block216) while the base layer is in the stretched configuration. In at leastone embodiment, the lining layer is also coupled to the base layer onthe opposite side of the base layer as the reinforcement layer and theauxetic layer while the base layer is in the stretched configuration(block 220). Finally, the base layer is released from the stretchedconfiguration and returns to the resting configuration (block 224). Dueto the cooperation between the auxetic structure of the auxetic layerand the stretch properties of the base layer in the panel, when the baselayer returns to the resting configuration, the panel buckles orpuckers. Specific embodiments of the methods for combining the layers ofthe panel are described in more detail below.

In some embodiments, the panel 100 is formed according to the generalmethod 200 above by adhesion. More specifically, in such embodiments,the auxetic structure 112 is formed on the substrate material 140 byadhesion, and the auxetic layer 110 is coupled to the reinforcementlayer 108 and the base layer 104 by adhesion.

In embodiments where the panel 100 is formed by adhesion, the auxeticstructure 112 is made of a thermoplastic adhesive material that isapplied to the resilient fabric material of the substrate material 140.Accordingly, the material forming the segments 24 of the auxeticstructure 112 is an adhesive that is activated when heated above apredefined temperature, binds to components that it contacts whileheated, and then resists separation from those components when cooledbelow the predefined temperature.

For example, the segments 24 of the auxetic structure 112 can becomprised of a polymer such as ethylene-vinyl acetate (EVA), athermoplastic such as nylon, or a thermoplastic elastomer such aspolyurethane. Each of these materials possesses elastomeric qualities ofsoftness and flexibility. In another exemplary embodiment, the segments24 are comprised of a thermoplastic foam, such as a thermoplasticpolyurethane (TPU) foam or an EVA foam, each of which is resilient andprovides a cushioning effect when compressed. While EVA and TPU foam aredisclosed herein as exemplary embodiments of the auxetic structure 112,it will be recognized by those of ordinary skill in the art that theauxetic structure 112 may alternatively be comprised of any of variousother thermoplastic adhesive materials. For example, in otheralternative embodiments, the auxetic layer may be comprised ofpolypropylene, polyethylene, XRD foam (e.g., the foam manufactured bythe Rogers Corporation under the name PORON®), or any of various otherpolymer materials exhibiting sufficient flexibility and elastomericqualities as well as appropriate thermoplastic and adhesive properties.In a further embodiment, the foam forming the auxetic layer is auxeticfoam. In at least one alternative embodiment, the auxetic structure 112can be made of a glue.

The segments 24 of the auxetic structure 112 may be formed on thesubstrate material 140 in any of various methods. By way of example, theauxetic structure 112 is formed on the substrate material 140 via amolding process such as compression molding or injection molding. By wayof further example, the auxetic structure 112 is formed on the substratematerial 140 via an additive manufacturing process such as selectivelaser sintering (SLS). In SLS, lasers (e.g., CO₂ lasers) fuse successivelayers of powdered material to form a three-dimensional structure. Onceformed, the auxetic structure 112 is coupled (e.g., attached, mounted,or adhered) to the substrate material 140. Specifically, the auxeticstructure 112 may be connected to the substrate material 140 using anyof various connection methods (examples of which are described infurther detail below).

In at least one embodiment, the auxetic structure 112 is printeddirectly on to the substrate material 140 using any of various printingmethods, as will be recognized by those of ordinary skill in the art.Alternatively, the auxetic structure 112 may first be printed on atransfer sheet, and then a heat transfer method may be used to transferthe auxetic structure 112 to the substrate material 140.

FIGS. 7A-7G provide a schematic illustration of an embodiment whereinthe panel 100 is formed by adhesion. As described in further detailbelow, the auxetic structure 112 is applied to the substrate material140 via adhesion, the auxetic structure 112 is also coupled to thereinforcement layer 108 by adhesion, the auxetic structure 112 iscoupled to the base layer 104 by adhesion, and the substrate material140 is coupled to the reinforcement layer 108 by the adhesion of theauxetic structure 112 to the reinforcement layer 108 and the base layer104.

As described in the method 200 in association with block 204, formingthe panel 100 includes first stretching the base layer 104 from theresting configuration (shown in FIG. 7A) into the stretchedconfiguration (shown in FIG. 7B) by applying tension in the direction ofthe arrows 40. As discussed above, the base layer 104 can be stretchedin either or both of the x-direction and the y-direction. By way ofexample, in FIGS. 7B-7E the arrows 40 are aligned along the x-directionof the material of the base layer 104. Additionally, the threads 124 ofthe base layer 104 are shown in a vertical configuration in FIGS. 7A-7Gmerely for the purpose of illustrating the locations of the threads 124and that there are openings 120 between the threads 124. Theillustrations shown in FIGS. 7A-7G are schematic representations only,and are not to scale. As shown in FIGS. 7A and 7B, stretching the baselayer 104 into the stretched configuration elongates the base layerthreads 124 and enlarges the base layer openings 120 (or increases thedistance between each of the base layer threads 124) relative to theresting configuration.

As shown in FIG. 7C (and described above in association with block 208of method 200), the reinforcement layer 108 is then applied or coupledto the base layer 104, while the base layer 104 is held in the stretchedconfiguration. By way of example, the reinforcement layer 108 is a sheetbonded or otherwise directly connected to a stretch fabric base layer104 such that the two layers 108 and 104 function as a unitarystructure. To this end, the reinforcement layer 108 may be connected tothe base layer 104 via adhesives, molding, welding, sintering, stitchingor any of various other means. In an embodiment, the reinforcement layer108 is brought into contact with the base layer 104 and then heat isapplied to place the material forming the reinforcement layer in asemi-liquid (partially melted) state such that material of thereinforcement layer in contact with the base layer infiltrates the baselayer fabric. Alternatively, the reinforcement layer is applied in amolten or semi-molten state. In either application, once cooled, thereinforcement layer 108 is securely fixed (permanently connected) to thefibers 124 of the base layer 104 such that any movement of the baselayer 104 is transferred to the reinforcement layer 108, and vice versa.

As shown in FIG. 7D (and described above in association with block 212of method 200), the auxetic structure 112, which is coupled to thesubstrate material 140 by adhesion, is arranged on the reinforcementlayer 108 opposite the base layer 104. The auxetic structure 112 isarranged on the reinforcement layer 108 while the base layer 104 isstill in the stretched configuration. As described above, the segments24 of the auxetic structure 112 are arranged in an auxetic pattern on afirst side of the substrate material 140. As shown in FIG. 7D, the firstside of the substrate material 140 is arranged on the reinforcementlayer 108. Accordingly, the auxetic structure 112 is arranged on thereinforcement layer 108 in this same auxetic pattern. As such, thesegments 24 of the auxetic structure 112 do not cover the entirety ofthe reinforcement layer 108.

As shown in FIG. 7E (and described above in association with block 216of method 200), heat is subsequently applied to the auxetic structure112, either directly or by heating at least one of the substratematerial 140, the reinforcement layer 108, and the base layer 104.Heating the auxetic structure 112 melts the thermoplastic material ofthe segments 24 (shown in FIGS. 3A-5B) of the auxetic structure 112 suchthat the thermoplastic material comes into contact with some of thereinforcement layer strands 132. Additionally, the melted thermoplasticmaterial at least partially fills the some of the relatively largereinforcement layer openings 128 such that the material passes throughthose reinforcement layer openings 128 and also comes into contact withsome of the base layer threads 124. Accordingly, the thermoplasticmaterial of the segments 24 of the auxetic structure 112 issimultaneously in contact with the substrate material 140, thereinforcement layer 108, and the base layer 104.

The material of the segments 24 binds to the reinforcement layer strands132 and the base layer threads 124 that it comes in contact with whileheated, and then resists separation from the reinforcement layer 108 andthe base layer 104 when cooled below the predefined temperature. Putanother way, the auxetic structure 112 is fused into the reinforcementlayer 108 and the base layer 104. The auxetic structure 112 is coupledto the reinforcement layer 108 and the base layer 104 while the baselayer 104 is still in the stretched configuration.

As shown in FIG. 7F (and described above in association with block 220of method 200), after the auxetic structure 112 is coupled to thereinforcement layer 108 and the base layer 104, the lining layer 116 isapplied to the base layer 104 opposite the reinforcement layer 108. Asmentioned above, in some alternative embodiments, the lining layer 116is not included in the panel 100. In embodiments where the panel 100includes a lining layer 116, the lining layer 116 is coupled (e.g.,mounted, attached, or fixed) to the base layer 104 by way of example, asan elastomer sheet bonded or otherwise directly connected to a stretchfabric base layer 104 such that the two layers 116 and 104 function as aunitary structure. To this end, the lining layer 116 may be connected tothe base layer 104 via adhesives, molding, welding, sintering, stitchingor any of various other means. In an embodiment, the lining layer 116 isbrought into contact with the base layer 104 and then heat is applied toplace the material forming the lining layer in a semi-liquid (partiallymelted) state such that material of the lining layer in contact with thebase layer infiltrates the base layer fabric. Alternatively, the lininglayer is applied in a molten or semi-molten state. In eitherapplication, once cooled, the lining layer 116 is securely fixed(permanently connected) to the fibers 124 of the base layer 104 suchthat any movement of the base layer 104 is transferred to the lininglayer 116, and vice versa.

The applied tension is then released from the base layer 104 to enablethe base layer 104 to return to the resting configuration (as describedabove in association with block 224 of method 200). Because the baselayer 104 is coupled to the auxetic structure 112 by the segments 24,when the material of the base layer 104 contracts to return to theresting configuration. As a result of the contraction of the base layer104, the auxetic structure contracts inwardly, and the panel 100 puckersor buckles (which puckering or buckling of the panel 100 and its variouslayers may be referred to herein as a “puckered configuration”).Depending on the strength of the auxetic structure, the puckering andbuckling may occur between the segments of the auxetic structure 112and/or along the segments 24 of the auxetic structure 112.

As illustrated by the dashed line D in FIG. 7F (where D lies in the x-yplane), this puckering or buckling raises and/or lowers the panel 100,including the substrate material 140, the auxetic structure 112, thereinforcement layer 108, the base layer 104, and the lining layer 116 inthe z-direction. Accordingly, when in the puckered configuration, thepanel 100 and one or more of its constituent layers are provided withpeaks, valleys and other surface irregularities in the z-direction. Putanother way, the puckering or buckling does not change the thickness ofthe panel 100 or of the layers of the panel 100 but forms a texturedsurface on the panel 100 wherein the layers of the panel 100 haveadditional dimensions in the z-direction.

Providing the panel 100 with surface irregularities in the z-directionwhen the base layer 104 is in the resting configuration (and the panel100 is in the puckered configuration) provides material in the panel 100that is available to flatten out when the panel 100 is stretched in thex-direction and/or the y-direction and therefore better accommodatesstretching of the article of apparel during wearing and/or use.Accordingly, the material of the lining layer 116 and the material ofthe reinforcement layer 108, each of which has a relatively high modulusof elasticity, are not required to stretch under the forces appliedduring normal donning, wearing, and/or using the article of apparel, butinstead flatten in the z-direction as the base layer 104 stretches inthe x-direction and/or y-direction under the forces applied duringnormal donning, wearing, and/or using the article of apparel.Additionally, the reinforcement layer 108, which has a relatively highmodulus of elasticity, limits the stretch of the panel 100 in thex-direction and/or the y-direction.

As shown in FIG. 7G, when the panel 100 is subsequently stretched underapplied tension during normal donning, wearing, and/or use of thearticle of apparel, the relative inelasticity of the material of thereinforcement layer 108 prevents stretching the panel 100 beyond thearrangement of the reinforcement layer 108 when the reinforcement layer108 is originally applied to the base layer 104. In other words, thereinforcement layer 108 is in a resting configuration when it is appliedto the base layer 104, which is in the stretched configuration. When thebase layer 104 contracts back to its resting configuration, thereinforcement layer 108 is in a contracted configuration (shown in FIG.7F). The reinforcement layer 108 thus limits the stretch of the panel100 back to the resting configuration of the reinforcement layer 108.This limitation of the amount of stretch of the panel 100 by thereinforcement layer 108 is also referred to as “lockout.”

Accordingly, the panel 100 is configured to stretch in the x-directionand/or the y-direction by stretching the base layer 104 in thex-direction and the y-direction. The auxetic shape of the panel 100provided by the auxetic structure 112 enables the substrate material140, the auxetic structure 112, the reinforcement layer 108, and thelining layer 116 to accommodate the stretch of the base layer 104 in thex-direction and/or the y-direction by flattening or rising in thez-direction. However, to protect the integrity of the panel 100 andprevent damage, the reinforcement layer 108 limits (or “locks out”) thestretch of the panel 100 in the x-direction and/or the y-direction.Accordingly, the reinforcement layer 108 provides structuralreinforcement and rigidity to the panel 100 while still accommodatingthe desired stretch in the x-direction and/or the y-direction.

When the base layer 104 is in the resting configuration, the surfaceirregularities of the panel 100 in the z-direction lifts some of thelining layer 116 away from the body of the wearer or user. In otherwords, less surface area of the panel 100 is in contact with the body ofthe wearer or user, which improves the fit as well as moisture wickingcapabilities of the article of apparel.

Moreover, because the auxetic structure 112 is integrated into the panel100 in this manner, the stretch of the base layer 104, the reinforcementlayer 108, and the panel 100 as a whole are guided by the auxeticstructure 112 in the manner described above with respect to thesubstrate material 140.

While the embodiment described above includes the auxetic structure 112formed as an adhesive material that infiltrates the reinforcement layer108 and binds to the base layer 104, in an alternative embodiment, theauxetic structure 112 can be formed on the substrate material 140, and aseparate adhesive material, for example, a glue, can be applied in theshape of the auxetic structure 112. In such embodiments, the separateadhesive material infiltrates the reinforcement layer 108 and binds tothe base layer 104 to impart the properties of the auxetic structure 112to the reinforcement layer 108 and the base layer 104.

In some embodiments, the panel 100 is formed according to the method 200above by stitching. More specifically, in such embodiments, the auxeticstructure 112 is formed on the substrate material 140 by stitching, andthe auxetic layer 110 is coupled to the reinforcement layer 108 and thebase layer 104 by stitching.

In embodiments where the panel 100 is formed by stitching, the auxeticstructure 112 is made of thread that is passed back and forth throughthe substrate material 140 to form the segments 24 on at least one of afirst side and a second side of the substrate material 140. Each ofthese materials possesses elastomeric qualities of softness andflexibility.

In other words, in embodiments wherein the auxetic structure 112 isformed on the substrate material 140 by stitching, the segments 24 areformed as stitches. The segments 24 may be formed in the substratematerial 140 in any of various stitching methods. By way of example, theauxetic structure 112 may be formed on the substrate material 140 viaembroidering or sewing, either by hand or by machine.

FIGS. 8A-8G provide a schematic illustration of an embodiment whereinpanel 100 is formed by stitching. As described in further detail below,the auxetic structure 112 is formed on the substrate material 140 viastitching, the auxetic structure 112 is also coupled to thereinforcement layer 108 and the base layer 104 by stitching, and thesubstrate material 140 is coupled to the reinforcement layer 108 and thebase layer 104 by the auxetic structure 112.

As described in the method 200 in association with block 204, formingthe panel 100 includes first stretching the base layer 104 from theresting configuration (shown in FIG. 8A) into the stretchedconfiguration (shown in FIG. 8B) by applying tension in the direction ofthe arrows 40. As discussed above, the base layer 104 can be stretchedin either or both of the x-direction and the y-direction. By way ofexample, in FIGS. 8B-8E the arrows 40 are aligned along the x-directionof the material of the base layer 104. Additionally, the threads 124 ofthe base layer 104 are shown in a vertical configuration in FIGS. 8A-8Gmerely for the purpose of illustrating the locations of the threads 124and that there are openings 120 between the threads 124. Theillustrations shown in FIGS. 8A-8G are schematic representations only,and are not to scale. As shown in FIGS. 8A and 8B, stretching the baselayer 104 into the stretched configuration elongates the base layerthreads 124 and enlarges the base layer openings 120 (or increases thedistance between each of the base layer threads 124) relative to theresting configuration.

As shown in FIG. 8C (and described above in association with block 208of method 200), the reinforcement layer 108 is then applied or coupledto the base layer 104, while the base layer 104 is held in the stretchedconfiguration. The reinforcement layer 108 is coupled to the base layer104, for example, in the manner described above with respect to FIG. 7C.

As shown in FIG. 8D (and described above in association with block 212of method 200), the substrate material 140 is then arranged on thereinforcement layer 108 opposite the base layer 104 while the base layer104 is in the stretched configuration. In embodiments wherein theauxetic structure 112 is formed by stitching, the auxetic structure 112is not formed on the substrate material 140 before the substratematerial 140 is arranged on the reinforcement layer 108. In at least oneembodiment, the substrate material 140 is coupled to the reinforcementlayer 108. By way of example, the substrate material 140 is an elastomersheet bonded or otherwise directly connected to the reinforcement layer108 such that the two layers 140 and 108 function as a unitarystructure. To this end, the substrate material 140 may be connected tothe reinforcement layer 108 via adhesives, molding, welding, sintering,stitching or any of various other means. In an embodiment, the substratematerial 140 is brought into contact with the reinforcement layer 108and then heat is applied to place the material forming the auxetic layerin a semi-liquid (partially melted) state such that material of theauxetic layer in contact with the reinforcement layer infiltrates thereinforcement layer. Alternatively, the substrate material 140 isapplied in a molten or semi-molten state. In either application, oncecooled, the substrate material 140 is securely fixed (permanentlyconnected) to the fibers 132 of the reinforcement layer 108 such thatany movement of the substrate material 140 is transferred to thereinforcement layer 108, and vice versa.

As shown in FIG. 8E (and described above in association with blocks 212and 216 of method 200), after the substrate material 140 has beenarranged on the reinforcement layer 108, the auxetic structure 112 isapplied to the substrate material 140, the reinforcement layer 108, andthe base layer 104 by stitching the thread of the auxetic structure 112through the substrate material 140, the reinforcement layer 108, and thebase layer 104 simultaneously to form the segments 24 of the auxeticshape. Accordingly, the auxetic structure 112 is arranged on thesubstrate material 140, the reinforcement layer 108, and the base layer104 in the same auxetic pattern described above.

Although in this embodiment, the auxetic structure 112 is applied to thesubstrate material 140, the substrate material 140 is not acting purelyas a substrate. More specifically, in this embodiment, the substratematerial 140 is acting as another layer in cooperation with the baselayer 104 to sandwich the reinforcement layer 108. The auxetic structure112 is then stitched through all three of the substrate material 140,the reinforcement layer 108, and the base layer 104.

As noted above, the segments 24 of the auxetic structure 112 may beformed in the substrate material 140 in any of various stitchingmethods. Accordingly, because the segments of the auxetic structure 112are simultaneously formed by stitching through the substrate material140, the reinforcement layer 108, and the base layer 104, the auxeticstructure 112 may be also formed on the reinforcement layer 108 and thebase layer 104 in any of various stitching methods, for example,embroidering or sewing, either by hand or by machine.

The segments 24 of the auxetic structure 112 do not cover the entiretyof the reinforcement layer 108, but the material of the auxeticstructure 112 at least partially fills some of the reinforcement layeropenings 128 as the material passes through those reinforcement layeropenings 128. Similarly, the material of the auxetic structure 112 atleast partially fills some of the base layer openings 120 as thematerial passes through those base layer openings 120. Accordingly, thematerial of the segments 24 of the auxetic structure is simultaneouslyin contact with the substrate material 140, the reinforcement layer 108,and the base layer 104, and binds those layers together.

As shown in FIG. 8F (and described above in association with block 220of method 200), after the auxetic structure 112 is coupled to thesubstrate material 140, the reinforcement layer 108, and the base layer104, the lining layer 116 is applied to the base layer 104 opposite thereinforcement layer 108. As mentioned above, in some alternativeembodiments, the lining layer 116 is not included in the panel 100. Inembodiments including a lining layer 116, the lining layer 116 iscoupled to the base layer 104, for example, in the manner describedabove with respect to FIG. 7F. In embodiments where the panel 100 isformed by stitching, the lining layer 116 is particularly useful forcovering the threads of the auxetic structure 112 that have passedthrough the base layer 104 as shown in FIG. 8F. Accordingly, althoughthe stitching is shown in FIG. 8F as extending partially into the lininglayer 116, this is shown to illustrate that in at least some embodimentsthe lining layer 116 covers the stitching that has passed through thebase layer 104, but the stitching does not pass partially into orthrough the lining layer 116. However, in at least some embodiments, thestitching may pass through the lining layer 116.

After the lining layer is applied to the base layer, the applied tensionis then released from the base layer 104 to enable the base layer 104 toreturn to the resting configuration (as described above in associationwith block 224 of method 200). Because the base layer 104 is coupled tothe auxetic structure 112 by the segments 24, when the material of thebase layer 104 contracts to return to the resting configuration, theremainder of the panel 100 puckers or buckles, including layers 108,110, and 116.

As illustrated by the dashed line D in FIG. 8F, this puckering orbuckling raises and lowers the substrate material 140, the auxeticstructure 112, the reinforcement 108, the base layer, and the lininglayer 116 in the z-direction. Accordingly, the panel 100 puckers orbuckles to provide the panel 100 with surface irregularities in thez-direction. As in embodiments wherein the auxetic structure 112 iscoupled by adhesion, in embodiments wherein the auxetic structure 112 iscoupled by stitching, the puckering or buckling does not change thethickness of the panel 100 or of the layer of the panel 100, but forms apatterned structure in the panel 100 along which layers of the panel 100are raised in the z-direction.

As discussed above with respect to embodiments wherein the auxeticstructure 112 is applied to the panel 100 by adhesion, in in embodimentswherein the auxetic structure 112 is applied to the panel 100 bystitching, providing the panel 100 with surface irregularities in thez-direction when the base layer 104 is in the resting configurationprovides material in the panel 100 that is available to flatten out whenthe panel 100 is stretched in the x-direction and/or the y-direction andtherefore better accommodates stretching of the article of apparelduring wearing and/or use. Accordingly, the material of the lining layer116 and the material of the reinforcement layer 108, each of which has arelatively high modulus of elasticity, are not required to stretch underthe forces applied during normal donning, wearing, and/or using thearticle of apparel, but instead flatten in the z-direction as the baselayer 104 stretches in the x-direction and/or y-direction under theforces applied during normal donning, wearing, and/or using the articleof apparel. Additionally, the reinforcement layer 108, which has arelatively high modulus of elasticity, limits the stretch of the panel100 in the x-direction and/or the y-direction.

As shown in FIG. 8G, when the panel 100 is subsequently stretched underapplied tension during normal donning, wearing, and/or use of thearticle of apparel, the relative inelasticity of the material of thereinforcement layer 108 resists stretching the panel 100 beyond thearrangement of the reinforcement layer 108 when the reinforcement layer108 is originally applied to the base layer 104. In other words, thereinforcement layer 108 is in a resting configuration when it is appliedto the base layer 104, which is in the stretched configuration. When thebase layer 104 contracts back to its resting configuration, thereinforcement layer 108 is in a contracted configuration (shown in FIG.8F). The reinforcement layer 108 thus limits the stretch of the panel100 back to the resting configuration of the reinforcement layer 108.This limitation of the amount of stretch of the panel 100 by thereinforcement layer 108 is also referred to as “lockout.”

Accordingly, the panel 100 is configured to stretch in the x-directionand/or the y-direction by stretching the base layer 104 in thex-direction and the y-direction. The auxetic shape of the panel 100provided by the auxetic structure 112 enables the substrate material140, the auxetic structure 112, the reinforcement layer 108, and thelining layer 116 to accommodate the stretch of the base layer 104 in thex-direction and/or the y-direction by flattening or rising in thez-direction. However, to protect the integrity of the panel 100 andprevent damage, the reinforcement layer 108 limits (or “locks out”) thestretch of the panel 100 in the x-direction and/or the y-direction.Accordingly, the reinforcement layer 108 provides structuralreinforcement and rigidity to the panel 100 while still accommodatingthe desired stretch in the x-direction and/or the y-direction.

When the base layer 104 is in the resting configuration, the surfaceirregularities of the panel 100 in the z-direction lifts some of thelining layer 116 away from the body of the wearer or user. In otherwords, less surface area of the panel 100 is in contact with the body ofthe wearer or user, which improves the fit as well as moisture wickingcapabilities of the article of apparel.

Moreover, because the auxetic structure 112 is integrated into the panel100 in this manner, the stretch of the base layer 104, the reinforcementlayer 108, and the panel 100 as a whole are guided by the auxeticstructure 112 in the manner described above with respect to thesubstrate material 140.

In embodiments of the panel 100 formed by either adhesion or stitching,the auxetic structure 112 can be applied in the arrangement shown inFIG. 3A or FIG. 3B. In embodiments wherein the auxetic structure 112 isapplied in the arrangement shown in FIG. 3A, upon being stretched, theauxetic shape will expand to the arrangement shown in FIG. 3B.Alternatively, in embodiments wherein the auxetic structure 112 isapplied in the arrangement shown in FIG. 3B, upon being stretched, theauxetic shape will further expand in the same manner to a furtherexpanded arrangement. Moreover, in embodiments wherein the auxeticstructure 112 is applied in the arrangement shown in FIG. 3B, whenapplied tension is released, the auxetic shape will contract to thearrangement shown in FIG. 3A. In embodiments wherein the auxeticstructure is applied in the arrangement shown in FIG. 3A, when appliedtension is released, the auxetic shape will further contract in the samemanner to a further contracted arrangement.

In some embodiments, the panel 100 is applied to articles of footwear,as illustrated in FIGS. 9A, 9B, 10 and 11A-11C. In such embodiments, theauxetic structure is selectively applied to particular regions of thearticle of footwear to provide expansion areas with controlled lockout.Each of the shoes 300 includes a forefoot region 304 arranged at theuser's forefoot when the shoe is worn, a midfoot region 308 arranged atthe user's midfoot and a heel region 312 arranged at the user's heelwhen the shoe is worn.

The shoe 300 shown in FIGS. 9A and 9B includes panels forming the rearof the upper. A first of the panels 100 is arranged at the midfootregion 308 and extends to the hindfoot region 312. A second of thepanels 100 is arranged at the heel region 312 and extends to the midfootregion 308. Accordingly, these regions 308, 312 of the shoe 300 exhibitthe stretch and the lockout properties imparted by the panel 100. Thiscan be advantageous to control the amount of stretch in the area of theuser's midfoot and heel.

The shoe 300, shown in FIG. 10, includes at least one panel 100 arrangedat the midfoot region 308, but does not include a panel 100 arranged atthe forefoot region 304 or the heel region 312. Accordingly, the midfootregion 304 of the shoe 300 exhibits the stretch and the lockoutproperties imparted by the panel 100. This can be advantageous tocontrol the amount of stretch in the area of the user's midfoot.Additionally, applying the auxetic structure to the midfoot region 308of the shoe 300 also provides the improved fit, comfort, and moisturewicking advantages, discussed above, to that region. In variousembodiments, the shoe 300 may include a panel 100 arranged at themidfoot region 308 on the lateral side of the shoe, facing toward theuser's midline, the medial side of the shoe, facing away from the user'smidline, or both.

In FIGS. 11A, 11B and 11C, the article of footwear includes a singlepanel 100 extending from the hindfoot region 312, through the midfoot308 region, and to the forefoot region 304, spanning the lateral andmedial sides of the shoe. With the configuration, the panel 100 enablesdynamic expansion of the upper during use (e.g., during a sportingactivity), with the auxetic structure expanding until the point oflockout as explained above.

The shoes 300 are provided as exemplary embodiments of articles offootwear including panels 100. In alternative embodiments, more or fewerpanels can be arranged in various locations on an article of footwear tocontrol the amount of stretch at each portion of the article of footwearas desired.

The foregoing detailed description of one or more exemplary embodimentsof the articles of apparel including auxetic structures has beenpresented herein by way of example only and not limitation. It will berecognized that there are advantages to certain individual features andfunctions described herein that may be obtained without incorporatingother features and functions described herein. Moreover, it will berecognized that various alternatives, modifications, variations, orimprovements of the above-disclosed exemplary embodiments and otherfeatures and functions, or alternatives thereof, may be desirablycombined into many other different embodiments, systems or applications.Presently unforeseen or unanticipated alternatives, modifications,variations, or improvements therein may be subsequently made by thoseskilled in the art which are also intended to be encompassed by theappended claims. Therefore, the spirit and scope of any appended claimsshould not be limited to the description of the exemplary embodimentscontained herein.

What is claimed is:
 1. An article of footwear comprising: a base layercomprising an elastic material, the base layer elastically deformablebetween a resting configuration and a stretched configuration, whereinthe base layer is stretched a stretch amount when in the stretchedconfiguration; an inelastic reinforcement layer coupled to the baselayer, the reinforcement layer configured to delimit the stretch amountof the base layer when the base layer is in the stretched configuration;and an auxetic structure coupled to the reinforcement layer.
 2. Thearticle of footwear of claim 1 wherein the reinforcement layer ispuckered when the base layer is in the resting configuration.
 3. Thearticle of footwear of claim 1, wherein the auxetic structure includes aplurality of interconnected segments defining a repeating pattern ofvoids, wherein each void has a reentrant shape.
 4. The article offootwear of claim 1, wherein: the auxetic structure is formed on asubstrate material, and the base layer and the substrate material arearranged on opposite facing sides of the reinforcement layer.
 5. Thearticle of footwear of claim 4, wherein: the auxetic structure is formedof an adhesive, the reinforcement layer comprises a plurality ofapertures, and the adhesive at least partially fills at least a portionof the plurality of apertures and simultaneously contacts the substratematerial, the reinforcement layer, and the base layer.
 6. The article offootwear of claim 4, wherein the auxetic structure is formed as aplurality of stitches that pass through the substrate material and thereinforcement layer such that the substrate material is coupled to thereinforcement layer and the reinforcement layer is coupled to the baselayer via the stitches.
 7. The article of footwear of claim 4, furthercomprising a lining layer coupled to the base layer such that the lininglayer and the reinforcement layer are arranged on opposite facing sidesof the base layer.
 8. An article of footwear, comprising: a solestructure; and an upper, the upper comprising: a base layer comprisingan elastic material, the base layer elastically deformable between aresting configuration and a stretched configuration, wherein the baselayer is stretched a stretch amount when in the stretched configuration,an inelastic reinforcement layer coupled to the base layer, wherein thereinforcement layer is in a puckered configuration when the base layeris in the resting configuration and the reinforcement layer isconfigured to delimit an amount of stretch of the base layer when thebase layer is in the stretched configuration, and a material applied tothe reinforcement layer, the material forming a structure defining arepeating pattern of perimeter walls and interior recesses.
 9. Thearticle of claim 8, wherein the material is a thread stitched throughthe reinforcement layer and the base layer.
 10. The article of claim 8,wherein: the material is an adhesive; the reinforcement layer comprisesa plurality of apertures; and the adhesive at least partially fills atleast a portion of the plurality of apertures and simultaneouslycontacts the reinforcement layer and the base layer.
 11. The article ofclaim 8, wherein: the material is included in a substrate; and the baselayer and the substrate are arranged on opposite facing sides of thereinforcement layer.
 12. A method of manufacturing a panel for afootwear upper, the method comprising: stretching a base layer from aresting configuration to a stretched configuration; coupling areinforcement layer to the base layer when the base layer is in thestretched configuration; applying an auxetic structure to thereinforcement layer when the base layer is in the stretchedconfiguration, the auxetic structure including a plurality ofinterconnected members defining a repeating pattern of voids, whereineach void has a reentrant shape; and releasing the base layer to allowthe base layer to return to the resting configuration.
 13. The method ofmanufacturing of claim 12, wherein applying the auxetic structure to thereinforcement layer includes: applying the auxetic structure to asubstrate material; and bringing the substrate material into contactwith the reinforcement layer.
 14. The method of manufacturing of claim13, wherein applying the auxetic structure to the substrate materialincludes printing the auxetic structure on the substrate material. 15.The method of manufacturing of claim 12, wherein applying the auxeticstructure to the reinforcement layer includes stitching the auxeticstructure in the reinforcement layer.
 16. The method of manufacturing ofclaim 12, wherein coupling the reinforcement layer to the base layer andapplying the auxetic structure to the reinforcement layer includescoupling the auxetic structure, the reinforcement layer, and the baselayer together as an interconnected unit when the base layer is in thestretched configuration.
 17. The method of manufacturing of claim 16,wherein coupling the auxetic structure, the reinforcement layer, and thebase layer together includes stitching the auxetic structure into thereinforcement layer and the base layer.
 18. The method of manufacturingof claim 16, wherein coupling the auxetic structure, the reinforcementlayer, and the base layer together includes fusing the auxetic structureinto the reinforcement layer and the base layer.
 19. The method ofmanufacturing of claim 18, wherein fusing the auxetic structure into thereinforcement layer and the base layer includes: applying a heatactivated adhesive material to a first side of a substrate material,arranging the first side of the substrate material on the reinforcementlayer, and heating the interconnected unit.
 20. The method ofmanufacturing of claim 12 further comprising coupling a lining layer tothe base layer when the base layer is in the stretched configuration.